638143437638 has 24 divisors (see below), whose sum is σ = 1114892426592. Its totient is φ = 273146861904.

The previous prime is 638143437593. The next prime is 638143437647. The reversal of 638143437638 is 836734341836.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4007006 + ... + 4163217.

It is an arithmetic number, because the mean of its divisors is an integer number (46453851108).

Almost surely, 2^638143437638 is an apocalyptic number.

638143437638 is a deficient number, since it is larger than the sum of its proper divisors (476748988954).

638143437638 is a wasteful number, since it uses less digits than its factorization.

638143437638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8171036 (or 8171029 counting only the distinct ones).

The product of its digits is 20901888, while the sum is 56.

The spelling of 638143437638 in words is "six hundred thirty-eight billion, one hundred forty-three million, four hundred thirty-seven thousand, six hundred thirty-eight".